Proteinaceous bioactive substances usable as test reagent and/or pharmaceutical, e.g. lymphokines and peptide hormones, have been extensively studied and developed as the recent remarkable advances in biochemistry and medical science. Some of these substances are commercialized or readily for commercialization.
Since proteinaceous bioactive substances are, in general, relatively unstable, a stabilizer must be added for their commercialization. The stabilizer most frequently used is human serum albumin (HSA). The use of HSA is, however, disadvantageous because:
(1) The stabilization effect on proteinaceous bioactive substances is unsatisfactory;
(2) The addition of HSA obscures the specific activity of the substance. A specific activty is represented by activity/mg protein, and used for determination of purification degree;
(3) The use of HSA has a fear of mediating human infectious diseases since HSA is a protein derived from human serum;
(4) HSA tends to form a water-insoluble solid on drying.
In order to avoid these demerits of HSA, various stabilizers have been proposed. As a stabilizer for IFN, Japan Patent Kokai No. 92,691/83 proposes cyclodextrin, and Japan Patent Kokai No. 25,333/84 proposes saccharides (excluding polysaccharides) such as mono- and oligo-saccharides, and polyols such as glycerine and ethylene glycol. For TNF stabilization, Japan Patent Kokai No. 39,829/84 proposes non-ionic surface active agents, and Japan Patent Kokai No. 59,625/84 proposes D-glucose, D-galactose, D-xylose, D-glucuronic acid, dextran, hydoxyethyl starch, and, preferably, trehalose. The stabilization effects attained with these stabilizers have proved insufficient. In addition, trehalose is relatively expensive. Thus, these stabilizers have not been in practical use.